1. Field of the Invention
The present invention relates to an audio decoding apparatus and method under the MPEG standard. More specifically, the present invention relates to an audio decoding apparatus and operating method for usage in a multiple-processor multimedia system including a scalar processor and a vector processor.
2. Description of the Related Art
Standardization of recording media, devices and various aspects of data handling, such as audio recording, storage and playback, is highly desirable for continued growth of this technology and its applications. One compression standard which has attained wide spread use for compressing and decompressing video information is the moving pictures expert group (MPEG) standard for audio and video encoding and decoding. The MPEG standard is defined in International Standard ISO/IEC 11172-1, "Information Technology--Coding of moving pictures and associated audio for digital storage media at up to about 1.5 Mbit/s", Parts 1, 2 and 3, First edition 1993-08-01 (hereinafter referred to as MPEG International Standard).
The MPEG International Standard addresses the problem of combining one or more data streams from video and audio sources with timing information to form a single information stream. Typically massive volumes of information stream data are handled by an MPEG processing system. Although the computing power of processors has advanced steadily and rapidly, the demand for higher processing power and computing efficiency remains unabated due to the development of aggressive new applications in the multimedia field that call for the display and performance of ever larger data quantities.
The MPEG International Standard defines a suitable audio decoding process which is illustrated in FIG. 1. The audio decoding process 10 includes the steps of inputting an encoded bit stream 12, decoding bit allocation bits 14, decoding scale factor selection information 16, requantization of sample data 18, synthesis of a subband filter 20, and outputting of pulse code modulated (PCM) samples 22.
The requantization operation 18 is one of the most computationally intensive operations performed by an MPEG audio decoder.
What is needed is an apparatus and technique that more efficiently performs audio decoding under the MPEG International Standard. More, specifically, what is needed is an apparatus and technique that more efficiently performs requantization of sample data in an audio decoder.